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• OpenCV compilation error in Fedora 21

  6 mars 2015, par eap

  I’ve got OpenCV source code from github and I get the following error when trying to compile it :

  /lib64/libavutil.so.54: undefined reference to `clReleaseMemObject@OPENCL_1.0'
  
  /lib64/libavutil.so.54: undefined reference to `clReleaseCommandQueue@OPENCL_1.0'
  
  /lib64/libavutil.so.54: undefined reference to `clCreateBuffer@OPENCL_1.0'
  
  /lib64/libavutil.so.54: undefined reference to `clBuildProgram@OPENCL_1.0'
  
  /lib64/libavutil.so.54: undefined reference to `clSetKernelArg@OPENCL_1.0'
  
  /lib64/libavutil.so.54: undefined reference to `clGetDeviceIDs@OPENCL_1.0'
  
  /lib64/libavutil.so.54: undefined reference to `clEnqueueUnmapMemObject@OPENCL_1.0'
  
  /lib64/libavutil.so.54: undefined reference to `clGetPlatformInfo@OPENCL_1.0'
  
  /lib64/libavutil.so.54: undefined reference to `clCreateProgramWithSource@OPENCL_1.0'
  
  /lib64/libavutil.so.54: undefined reference to `clGetDeviceInfo@OPENCL_1.0'
  
  /lib64/libavutil.so.54: undefined reference to `clReleaseContext@OPENCL_1.0'
  
  /lib64/libavutil.so.54: undefined reference to `clCreateContextFromType@OPENCL_1.0'
  
  /lib64/libavutil.so.54: undefined reference to `clCreateCommandQueue@OPENCL_1.0'
  
  /lib64/libavutil.so.54: undefined reference to `clEnqueueMapBuffer@OPENCL_1.0'
  
  /lib64/libavutil.so.54: undefined reference to `clGetPlatformIDs@OPENCL_1.0'

  My machine is a laptop with Intel i7 and a GT630M graphics card and I’m using Bumblebee.

  Thanks.

• opencv ffmpeg vaapi 1080p resolution not working

  18 avril 2023, par yeo

  I want to use hardware acceleration with opencv manual build.
My gpu uses an i965 intel cpu built-in graphics card, and it is a debain11 environment.

  


  [OPENCV:FFMPEG:40] Reinit context to 1920x1088, pix_fmt: vaapi_vld


  


  If you look at some of the error messages below, it seems that the original file is 1920x1080 because it is converted to 1088 while reinit.
I've read that vaapi_vld reads 16 bits at a time.
In fact, it seems to work when the original file is changed to 1920x1072.
Is there a way to fix it without changing the original file resolution ?
Please advise seniors.
Sorry for my poor English skills
Thank you

  


  manual build CMAKE option

  


  "-DCMAKE_VERBOSE_MAKEFILE=ON -DWITH_VA_INTEL=ON -DWITH_VA=ON -DOPENCV_FFMPEG_ENABLE_LIBAVDEVICE=ON -DOPENCV_ENABLE_GLX=ON -DOPENCV_FFMPEG_SKIP_BUILD_CHECK=ON -DWITH_OPENVINO=ON -DWITH_INF_ENGINE=ON"



  


  build infomation

  


    OpenCV modules:
    To be built:                 calib3d core dnn features2d flann gapi highgui imgcodecs imgproc ml objdetect photo python3 stitching video videoio
    Disabled:                    world
    Disabled by dependency:      -
    Unavailable:                 java python2 ts
    Applications:                -
    Documentation:               NO
    Non-free algorithms:         NO

  GUI:                           GTK3
    GTK+:                        YES (ver 3.24.24)
      GThread :                  YES (ver 2.66.8)
      GtkGlExt:                  NO
    VTK support:                 NO
  Media I/O: 
    ZLib:                        /usr/lib/x86_64-linux-gnu/libz.so (ver 1.2.11)
    JPEG:                        /usr/lib/x86_64-linux-gnu/libjpeg.so (ver 62)
    WEBP:                        /usr/lib/x86_64-linux-gnu/libwebp.so (ver encoder: 0x020e)
    PNG:                         /usr/lib/x86_64-linux-gnu/libpng.so (ver 1.6.37)
    TIFF:                        /usr/lib/x86_64-linux-gnu/libtiff.so (ver 42 / 4.2.0)
    JPEG 2000:                   build (ver 2.4.0)
    OpenEXR:                     build (ver 2.3.0)
    HDR:                         YES
    SUNRASTER:                   YES
    PXM:                         YES
    PFM:                         YES
  Video I/O:
    DC1394:                      YES (2.2.6)
    FFMPEG:                      YES
      avcodec:                   YES (58.91.100)
      avformat:                  YES (58.45.100)
      avutil:                    YES (56.51.100)
      swscale:                   YES (5.7.100)
      avresample:                YES (4.0.0)
    GStreamer:                   YES (1.18.4)
    v4l/v4l2:                    YES (linux/videodev2.h)

  Parallel framework:            pthreads

  Trace:                         YES (with Intel ITT)

  Other third-party libraries:
    Intel IPP:                   2020.0.0 Gold [2020.0.0]
    VA:                          YES
    Lapack:                      NO
    Eigen:                       NO
    Custom HAL:                  NO
    Protobuf:                    build (3.19.1)

  OpenCL:                        YES (INTELVA)
    Include path:                /home/xxx
    Link libraries:              Dynamic load

  Python 3:
    Interpreter:                 /usr/bin/python3 (ver 3.9.2)
    Libraries:                   /usr/lib/x86_64-linux-gnu/libpython3.9.so (ver 3.9.2)
    numpy:                       /home/../include (ver 1.19.3)
    install path:                python/cv2/python-3


  


  vainfo

  


  libva info: VA-API version 1.10.0
libva info: User environment variable requested driver 'i965'
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/i965_drv_video.so
libva info: Found init function __vaDriverInit_1_8
libva info: va_openDriver() returns 0
vainfo: VA-API version: 1.10 (libva 2.10.0)
vainfo: Driver version: Intel i965 driver for Intel(R) Haswell Mobile - 2.4.1
vainfo: Supported profile and entrypoints
      VAProfileMPEG2Simple            : VAEntrypointVLD
      VAProfileMPEG2Simple            : VAEntrypointEncSlice
      VAProfileMPEG2Main              : VAEntrypointVLD
      VAProfileMPEG2Main              : VAEntrypointEncSlice
      VAProfileH264ConstrainedBaseline: VAEntrypointVLD
      VAProfileH264ConstrainedBaseline: VAEntrypointEncSlice
      VAProfileH264Main               : VAEntrypointVLD
      VAProfileH264Main               : VAEntrypointEncSlice
      VAProfileH264High               : VAEntrypointVLD
      VAProfileH264High               : VAEntrypointEncSlice
      VAProfileH264MultiviewHigh      : VAEntrypointVLD
      VAProfileH264MultiviewHigh      : VAEntrypointEncSlice
      VAProfileH264StereoHigh         : VAEntrypointVLD
      VAProfileH264StereoHigh         : VAEntrypointEncSlice
      VAProfileVC1Simple              : VAEntrypointVLD
      VAProfileVC1Main                : VAEntrypointVLD
      VAProfileVC1Advanced            : VAEntrypointVLD
      VAProfileNone                   : VAEntrypointVideoProc
      VAProfileJPEGBaseline           : VAEntrypointVLD


  


  import os
import cv2

os.environ["OPENCV_FFMPEG_CAPTURE_OPTIONS"] = "hw_decoders_any;vaapi,vdpau" +

cap = cv2.VideoCapture(file_name,cv2.CAP_FFMPEG(cv2.CAP_PROP_HW_ACCELERATION,cv2.VIDEO_ACCELERATION_ANY))  



  


  error code

  


  [ INFO:0@0.187] global /home/u/opencv-python/opencv/modules/videoio/src/videoio_registry.cpp (223) VideoBackendRegistry VIDEOIO: Enabled backends(8, sorted by priority): FFMPEG(1000); GSTREAMER(990); INTEL_MFX(980); V4L2(970); CV_IMAGES(960); CV_MJPEG(950); FIREWIRE(940); UEYE(930)
[OPENCV:FFMPEG:40] Reinit context to 1920x1088, pix_fmt: yuv420p
[OPENCV:FFMPEG:40] Trying to use DRM render node for device 0.
[OPENCV:FFMPEG:40] libva: VA-API version 1.10.0
libva: User environment variable requested driver 'i965'
libva: Trying to open /usr/lib/x86_64-linux-gnu/dri/i965_drv_video.so
libva: Found init function __vaDriverInit_1_8
libva: va_openDriver() returns 0
Initialised VAAPI connection: version 1.10
[OPENCV:FFMPEG:40] VAAPI driver: Intel i965 driver for Intel(R) Haswell Mobile - 2.4.1.
[OPENCV:FFMPEG:40] Driver not found in known nonstandard list, using standard behaviour.
[ INFO:0@0.228] global /home/u/opencv-python/opencv/modules/videoio/src/cap_ffmpeg_hw.hpp (276) hw_check_device FFMPEG: Using vaapi video acceleration on device: Intel i965 driver for Intel(R) Haswell Mobile - 2.4.1
[ INFO:0@0.228] global /home/u/opencv-python/opencv/modules/videoio/src/cap_ffmpeg_hw.hpp (566) hw_create_device FFMPEG: Created video acceleration context (av_hwdevice_ctx_create) for vaapi on device 'default'
[ INFO:0@0.228] global /home/u/opencv-python/opencv/modules/core/src/ocl.cpp (1186) haveOpenCL Initialize OpenCL runtime...
[ INFO:0@0.228] global /home/u/opencv-python/opencv/modules/core/src/ocl.cpp (1192) haveOpenCL OpenCL: found 0 platforms
File open : ./videoplayback1.mp4
[OPENCV:FFMPEG:40] Reinit context to 1920x1088, pix_fmt: vaapi_vld
[OPENCV:FFMPEG:16] Failed to read image from surface 0x4000014: 18 (invalid parameter).
[ERROR:0@0.245] global /home/u/opencv-python/opencv/modules/videoio/src/cap_ffmpeg_impl.hpp (1575) retrieveFrame Error copying data from GPU to CPU (av_hwframe_transfer_data)
Play video ... size=1920x1080, file=./videoplayback1.mp4
[OPENCV:FFMPEG:16] Failed to read image from surface 0x4000012: 18 (invalid parameter).
[ERROR:0@0.277] global /home/u/opencv-python/opencv/modules/videoio/src/cap_ffmpeg_impl.hpp (1575) retrieveFrame Error copying data from GPU to CPU (av_hwframe_transfer_data)
OpenCV(4.6.0) Error: Assertion failed (!image.empty()) in imencode, file /home/u/opencv-python/opencv/modules/imgcodecs/src/loadsave.cpp, line 976
err =  OpenCV(4.6.0) /home/u/opencv-python/opencv/modules/imgcodecs/src/loadsave.cpp:976: error: (-215:Assertion failed) !image.empty() in function 'imencode'



  


  I tried to do video capture by ffmpeg hwacceleration with opencv, but an error message occurred

  


• Increasing Website Traffic : 11 Tips To Attract Visitors

  25 août 2023, par Erin — Analytics Tips, Marketing

  For your website and business to succeed, you need to focus on building traffic.

  However, you aren’t the only one with that goal in mind.

  There are millions of other websites trying to increase their traffic as well. With that much competition, it’s important to make sure your website stands out. Accomplishing that can require a great deal of strategy.

  We’ve compiled a list of tips to help you develop a solid plan for increasing website traffic, to expand your reach, grow your audience and boost customer engagement levels — creating more opportunities for your business.Using these tips, more visitors will find their way to your website — meaning more customers for your business.

  Why is website traffic important ?

  Website traffic is essentially the number of people visiting your website. When someone lands on your site, they’re considered a visitor and increase your website traffic. 

  When your website traffic is high, you’ll get more clicks, customer interactions and brand engagement. As a result, search engines will have a positive impression of your website and send more people there, meaning even more people will see your content and have the opportunity to buy your product.

  When using a website for your business or any other venture, tracking your website traffic using a web analytics solution like Matomo is critical.

  

  With over 200 million actively maintained and visited websites in 2023, it’s important to make sure yours stands out if you want to increase your website traffic and grow your online presence. 

  11 tips for increasing website traffic

  Here are 11 tips to increase your organic traffic and elevate your business.

  1. Perfect your SEO

  Optimising your website to show up in search engine results shouldn’t be overlooked, as 63% of consumers start researching a product by using a search engine. Search engine optimisation, or SEO, increases the visibility and discoverability of your website on search engine results pages (SERPs). SEO targets organic searches, which means it doesn’t add to social media traffic, direct traffic or referrals, and it isn’t paid traffic.

  SEO is number one on this list for a reason — most of these tips will directly, or indirectly, improve your SEO efforts. 

  Steps to improve your search engine optimisation can include :

  • Using relevant keywords that are incorporated naturally throughout your content
  • Using a web analytics tool like Matomo, with its search keyword feature, to gain insights and identify opportunities for improvement
  • Using descriptive meta titles and meta descriptions
  • Link to your own content internally with descriptive anchor tags, and make sure unused pages are removed 
  • Keeping your target audience in mind and marketing your content toward them
  • Making sure your website’s structure is optimised to be mobile-friendly, fast and responsive — such as with Matomo’s SEO Web Vitals feature, which monitors key metrics like your website’s page speed and loading performance, pivotal for optimising search engine results

  2. Research the competition

  It’s important to remember that while your business might be unique, it’s likely not the only one in its field. Thousands of other websites from other companies are also looking to improve their website traffic and increase sales, and you have to outcompete them.

  Looking at what your competitors are doing is vital from a strategic perspective. You can see what their content looks like, how they’re framing their specific use cases and what target audience they’re marketing toward.

  Knowing what your competitors are doing can help you find ways to improve your content and make it unique. Are your competitors missing a specific use case or neglecting a particular audience ? Fill in their content gaps on your website, and pick up the traffic they’re missing.

  3. Create high-quality, evergreen content

  If your content is high-quality, visitors will read more of it and stay longer on your site. This obviously increases the likelihood they will purchase your product or service, and it tells search engines that your website is a good answer for a search query.

  High-quality content will also be shared more often, leading to even more website traffic. You should aim to develop content that doesn’t lose relevance over time (aka “evergreen content”). If you include time-sensitive data, statistics or content in your website, blog posts or articles, it’ll be relevant only around that time frame. 

  While this month’s viral content is highly popular, it likely won’t be relevant in a few months. Instead, if you ensure your content is evergreen, it will continue to get engagement long after it’s published.

  4. Implement creative visuals

  It’s important to have engaging, fun and interactive media on your website to keep visitors on your site longer. Like good content, interesting visuals (and the resulting longer visits) can translate to more purchases (and favourable assessments by search engines).

  

  Media can take the form of videos, infographics, images or web graphics. 

  With Matomo’s Media Analytics feature, you can automatically gain even deeper insights into how your visitors engage with your media content, enhancing your understanding of their preferences and behaviours.

  If you have interesting, captivating visuals, visitors will be more likely to stay on your website longer and see what you have to offer. Without captivating visuals to break up walls of text, you’ll likely find visitors will tend to leave your site in favour of something more engaging.

  Just make sure you design your visuals with your target audience in mind. Flashy, fun graphics might not be a good fit for a professional audience, but they’re great for younger audiences. If you get your audience correct, they may also share the images with others. Depending on your business, that might be a useful infographic shared across LinkedIn, or a picture of a clever use case shared on Pinterest. 

  As a bonus, if other companies use your graphics on their websites, that earns you some backlinks — more on those in a bit.

  5. Create a comprehensive knowledge base

  Having a knowledge base is critical to making sure your service or product is well understood and well documented, especially in the tech industry. If a visitor or potential customer is interested in your product or service, they need to know exactly what it will do for them and that they have a good foundation of support in case they need help. A knowledge base is also a good place for internal links (more on those in a bit).

  Visitors can also use your knowledge base as a source of information, and if they cite you as a source, that’ll lead right back to more website traffic for you (see our backlinks section for more about this). If your website is a good source of information, visitors will come back to it again and again.

  6. Use social media often and consistently

  Digital marketing nowadays heavily relies on social media platforms. Having an online presence no longer means just having a website — if you’re not using social media sites, you’re missing out on a huge portion of potential visitors and customers.

  A strong social media presence with profiles on platforms like Facebook, X (formerly Twitter), Instagram or LinkedIn can be invaluable for increasing your website traffic. Visitors to your social media profiles will click on regularly shared content, read your blog posts and possibly become customers.

  Participating in relevant communities and networking with other companies in groups in your industry can also be invaluable. If you participate in online communities and forums for your niche, you can offer insight, answer questions and plug your website. All of this will increase your clicks, which will increase your website traffic.

  If you’ve managed to build your own community on social media, make sure to keep them engaged ! Implementing your own forum, hosting live chats and Q&As, offering helpful and engaging content will make sure visitors keep coming back and spreading the word. 

  7. Use email marketing or newsletters

  Having an email list and sending marketing emails or newsletters is a great way to increase website traffic. You can offer exclusive content, and promise discounts or resources to your subscribers for when they return to your website. This will help keep your loyal audience engaged, entice new customers to subscribe to your newsletter, give you a chance to upsell to people who have already expressed an interest in your product and potentially convert curious subscribers into customers.

  8. Make sure your content can earn backlinks

  A backlink is when a website links to a different website — ideally using relevant anchor text — and it’s an effective strategy for increasing referral traffic, that is, visitors who get to your website via a link on another website. The more backlinks you have, the more your referral traffic will increase. Social share buttons make it easy for people to cite you on social platforms, too. 

  We’ve already talked about making expert content that’s link-worthy, but also make sure that you’re creating linkable assets (like those interesting visuals mentioned earlier), building relationships with other sites that will link to you (like by inviting an expert or influencer to write on your page and promote it from their platform, or by writing your own guest content for their sites) and sharing your own content. All of this can help increase your referral traffic, particularly when you’re linked from websites with a higher domain authority than you have.

  You can also make sure your website is listed in online directories. Some sites will do interviews and roundups, as well — these are great opportunities to increase your backlinks.

  9. Optimise your CTR

  Click-through rate, or CTR, is the percentage of users who click on specific links to your website. A high CTR means your visitors are following a link — whether in an advertisement, a search result or a social media post — and a low CTR means they’re passing it by. Optimising your CTR can greatly improve your website traffic.

  To improve CTR, identify successful elements such as copy, imagery, and offers in your ads, enabling you to amplify effective elements and minimise less impactful ones.

  10. Ensure your website is responsive and mobile-friendly

  If a visitor is frustrated by your site being slow, laggy, clunky or not mobile-friendly, they won’t stay long. That doesn’t look good to search engines if that’s how your visitors got there. Your website needs to be clean, responsive, user-friendly and accessible.

  If your website is slow, try increasing your website’s performance by :

  • Optimising images : Reduce the size of images and compress them for faster load times. Opt for JPEG format for photos and PNG format for graphics. 
  • Limit the use of plugins : If you are using a CMS like WordPress, consider removing plugins that are unnecessary or not essential.
  • Embrace lazy loading : To further enhance site speed and reduce initial load times, set up your site to load images and content only as visitors scroll down. Prioritising the content and images at the top of the page makes the site feel faster. Some CMS platforms will offer this option, but others may require a bit of coding to set this up. 

  Many people rely on their phones to research services or products, especially if they’re doing a quick search. Make sure your website is friendly to mobile users. It should scale vertically and scroll smoothly so users aren’t frustrated when using your site. They should be able to find the info they need immediately without any technical issues.

  11. Track your website’s metrics

  As you test out each of these strategies to increase your web traffic, don’t forget to closely analyse the performance of your site. To truly understand the impact of your efforts, you’ll need a reliable web analytics solution. Think of a dependable web analytics solution as your website’s GPS. Without it, you’d be lost, unsure of your direction and missing out on valuable insights to steer your growth.

  Matomo is a powerful web analytics tool that can help you do just that by providing information on your site visitors and campaign performance, complemented by an array of behavioural analytics features that delve into user interactions. Among these, our heatmap feature stands out, enabling greater insights into user interactions and optimisation of your site’s effectiveness.

  

  Google Analytics is another powerful analytics option, though it has challenges with data accuracy ; there are multiple other web analytics solutions as well.

  Regardless of what web analytics solution you choose, the process of analysing your website metrics is incredibly important for identifying areas of improvement to increase website traffic.

  Increasing your web traffic is a process

  Increasing website traffic isn’t something you accomplish overnight. It’s a comprehensive, ongoing endeavour that requires constant analysis and fine-tuning. 

  By applying these tips to create consistent, high-quality content that gets spotlighted on search engines, shared on social media and returned to again and again, you’ll see a steady stream of increased traffic. 

  With Matomo, you can understand your visitor behaviour to see what works and what doesn’t as you work to increase your website traffic. Get your free 21-day trial now. No credit card required.